Such electrical switches are used for switching on and off electrical devices supplied by a voltage source. In particular, some switches are used in electrical tools having an electric motor. A switch may also contain a control electronics device so that, in addition to switching the electric motor on and off, it is also possible to use the switch to adjust the rotation speed of the electric motor to correspond to a nominal value which can be preset.
DE-A1-28 38 934 discloses an electrical switch for switching on and off as well as for adjusting the rotation speed of an electric motor. The switch has a housing with two input connections located on or in the housing for the electrical connection to the voltage source, and two output connections for the electrical connection to the electric motor. The control electronics device and two contact systems, which each comprise a fixed contact as well as a switching contact, are arranged in the housing. The switching contact is, in turn, designed as a contact rocker having two lever arms and a rotating bearing, the first lever arm, which interacts with the fixed contact, being loaded by a spring force in the closing direction toward the fixed contact. An operating element which is designed as a push button and can be moved manually is located on the housing. During its movement, the operating element acts on the second lever arm on the switching contact of the respective contact system in such a manner that the first lever arm can be placed against the fixed contact in order to close the electrical connection of the contact system. Furthermore, the operating element interacts with the control electronics device, so that a rotation speed corresponding to the setting of the operating element can be set on the electric motor by the control electronics device.
A further electrical switch for switching on and off as well as for adjusting the rotation speed of an electric motor is disclosed in DE-C2-40 38 787. The housing of this switch contains a control electronics device, as well as two contact systems, which are each composed of two fixed contacts and a spring-loaded contact link.
The first fixed contact is arranged on a contact path, which is connected to an input connection, and the second fixed contact is arranged on a contact bracket, which is connected to the control electronics device. The contact link is placed by the operating element against the two fixed contacts, via a switching stud, in order to close the electrical connection of the contact system. The contact system of this switch is sensitive to tolerances and is also complex to assemble.
In handheld electrical tools, such switches are generally installed in the handle. Owing to their functionality, the known switches have a complex design, so that the housing needs to have a certain physical size, which in turn has to be accommodated in the handle. In many cases, in order to improve the ergonomics of the electrical tool, it is desirable to design the handle to be narrower or thinner. In these cases, the space available for installation may no longer be sufficient for the known switches.